Transmission spectra of single fibers from both natural and synthetic sources were recorded in the infrared by the use of a microscope FTIR Spectrometer. Raman (scattering) spectra were recorded as well, and used to further discriminate fibers from closely related polymers, fibers with differing finishes, and fibers dyed by in-situ development processes. Details of experimental technique and limitations of the method are described. -- AATA